package com.yiliao.util;

import java.security.MessageDigest;
import java.util.Arrays;

/**
 * SHA1 class
 * 
 * 计算公众平台的消息签名接口.
 */
public class SHA1 {

	/**
	 * 用SHA1算法生成安全签名
	 * 
	 * @param token
	 *            票据
	 * @param timestamp
	 *            时间戳
	 * @param nonce
	 *            随机字符串
	 * @param encrypt
	 *            密文
	 * @return 安全签名
	 * @throws AesException
	 */
	public static String getSHA1(String Jsapi_ticket, String timestamp, String nonce,
			String httpUrl) {
		try {
			String[] array = new String[] {Jsapi_ticket, timestamp, nonce, httpUrl};
			StringBuffer sb = new StringBuffer();
			// 字符串排序
			Arrays.sort(array);
			for (int i = 0; i < 4; i++) {
				if(sb.toString()!=null && !sb.toString().equals(""))
					sb.append("&");
				sb.append(array[i]);
			}
			String str = sb.toString();
			System.out.println("string1--->"+sb.toString());
			// SHA1签名生成
			MessageDigest md = MessageDigest.getInstance("SHA-1");
			md.update(str.getBytes());
			byte[] digest = md.digest();

			StringBuffer hexstr = new StringBuffer();
			String shaHex = "";
			for (int i = 0; i < digest.length; i++) {
				shaHex = Integer.toHexString(digest[i] & 0xFF);
				if (shaHex.length() < 2) {
					hexstr.append(0);
				}
				hexstr.append(shaHex);
			}
			return hexstr.toString();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
}
